Merge changes I209e3ec7,If70df129 into main

* changes:
  Change collapse to use adapterItems instead of getting the childCount()
  Upon expanding, expand just enough so the header shows.

src/com/android/launcher3/allapps/ActivityAllAppsContainerView.java

@@ -189,6 +189,7 @@ public class ActivityAllAppsContainerView<T extends Context & ActivityContext>
     private float mBottomSheetAlpha = 1f;
     private boolean mForceBottomSheetVisible;
     private int mTabsProtectionAlpha;
+    private float mTotalHeaderProtectionHeight;
     @Nullable private AllAppsTransitionController mAllAppsTransitionController;
 
     private PrivateSpaceHeaderViewController mPrivateSpaceHeaderViewController;
@@ -1431,9 +1432,11 @@ public class ActivityAllAppsContainerView<T extends Context & ActivityContext>
                 mTmpPath.reset();
                 mTmpPath.addRoundRect(mTmpRectF, mBottomSheetCornerRadii, Direction.CW);
                 canvas.drawPath(mTmpPath, mHeaderPaint);
+                mTotalHeaderProtectionHeight = headerBottomWithScaleOnTablet;
             }
         } else {
             canvas.drawRect(0, 0, canvas.getWidth(), headerBottomWithScaleOnPhone, mHeaderPaint);
+            mTotalHeaderProtectionHeight = headerBottomWithScaleOnPhone;
         }
 
         // If tab exist (such as work profile), extend header with tab height
@@ -1463,9 +1466,18 @@ public class ActivityAllAppsContainerView<T extends Context & ActivityContext>
                     right,
                     tabBottomWithScale,
                     mHeaderPaint);
+            mTotalHeaderProtectionHeight = tabBottomWithScale;
         }
     }
 
+    /**
+     * The height of the header protection is dynamically calculated during the time of drawing the
+     * header.
+     */
+    float getHeaderProtectionHeight() {
+        return mTotalHeaderProtectionHeight;
+    }
+
     /**
      * redraws header protection
      */